﻿var Fireworks = function () {//Fireworks烟灰
    //产生烟花随机数
    var self = this;//self：自己
    //按位取反运算符
    var rand = function (rMi, rMa) { return ~~((Math.random() * (rMa - rMi + 1)) + rMi); }//~~取整 rand随机函数
    var hitTest = function (x1, y1, w1, h1, x2, y2, w2, h2) { return !(x1 + w1 < x2 || x2 + w2 < x1 || y1 + h1 < y2 || y2 + h2 < y1); };
    //请求动画帧
    //requestAnimationFrame：缓存函数
    //用法
    window.requestAnimFrame = function () { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (a) { window.setTimeout(a, 1E3 / 60) } }();//每秒60帧

    self.init = function () {
        self.canvas = document.createElement('canvas'); //在对象中创建一个canvas对象；
        //canvas 全屏            
        self.canvas.width = self.cw = $(window).innerWidth();//获取当前窗口的宽度(包含滚动条)
        self.canvas.height = self.ch = $(window).innerHeight();//获取当前窗口的高度(包含滚动条)         
        self.particles = [];    //particles:粒子，原子
        self.partCount = 150;
        self.fireworks = [];
        self.mx = self.cw / 2;
        self.my = self.ch / 2;
        self.currentHue = 30;
        self.partSpeed = 5;
        self.partSpeedVariance = 10;
        self.partWind = 50;
        self.partFriction = 5;
        self.partGravity = 1;
        self.hueMin = 0;
        self.hueMax = 360;
        self.fworkSpeed = 4;
        self.fworkAccel = 10;
        self.hueVariance = 30;
        self.flickerDensity = 25;
        self.showShockwave = true;
        self.showTarget = false;
        self.clearAlpha = 25;

        $(document.body).append(self.canvas);
        self.ctx = self.canvas.getContext('2d');
        self.ctx.lineCap = 'round';
        self.ctx.lineJoin = 'round';
        self.lineWidth = 1;
        self.bindEvents();
        self.canvasLoop();

        self.canvas.onselectstart = function () {//onselectstart几乎可以用于所有对象，其触发时间为目标对象被开始选中时(即选中动作刚开始，尚未实质性被选中)
            return false;//现对文本的选择与否的控制，
            //onselectstart="return true" -- 可选，是默认项，false -- 不可选
            return false;
        };
    };
    //创建粒子
    self.createParticles = function (x, y, hue) {
        var countdown = self.partCount;
        while (countdown--) {
            var newParticle = {
                x: x,
                y: y,
                coordLast: [
                    { x: x, y: y },
                    { x: x, y: y },
                    { x: x, y: y }
                ],
                angle: rand(0, 360),
                speed: rand(((self.partSpeed - self.partSpeedVariance) <= 0) ? 1 : self.partSpeed - self.partSpeedVariance, (self.partSpeed + self.partSpeedVariance)),
                friction: 1 - self.partFriction / 100,
                gravity: self.partGravity / 2,
                hue: rand(hue - self.hueVariance, hue + self.hueVariance),
                brightness: rand(50, 80),
                alpha: rand(40, 100) / 100,
                decay: rand(10, 50) / 1000,
                wind: (rand(0, self.partWind) - (self.partWind / 2)) / 25,
                lineWidth: self.lineWidth
            };
            self.particles.push(newParticle);
        }
    };

    // 更新粒子
    self.updateParticles = function () {
        var i = self.particles.length;
        while (i--) {
            var p = self.particles[i];
            var radians = p.angle * Math.PI / 180;
            var vx = Math.cos(radians) * p.speed;
            var vy = Math.sin(radians) * p.speed;
            p.speed *= p.friction;

            p.coordLast[2].x = p.coordLast[1].x;
            p.coordLast[2].y = p.coordLast[1].y;
            p.coordLast[1].x = p.coordLast[0].x;
            p.coordLast[1].y = p.coordLast[0].y;
            p.coordLast[0].x = p.x;
            p.coordLast[0].y = p.y;

            p.x += vx;
            p.y += vy;
            p.y += p.gravity;

            p.angle += p.wind;
            p.alpha -= p.decay;

            if (!hitTest(0, 0, self.cw, self.ch, p.x - p.radius, p.y - p.radius, p.radius * 2, p.radius * 2) || p.alpha < .05) {
                self.particles.splice(i, 1);
            }
        };
    };
    // 绘制粒子     
    self.drawParticles = function () {
        var i = self.particles.length;
        while (i--) {
            var p = self.particles[i];

            var coordRand = (rand(1, 3) - 1);
            self.ctx.beginPath();
            self.ctx.moveTo(Math.round(p.coordLast[coordRand].x), Math.round(p.coordLast[coordRand].y));
            self.ctx.lineTo(Math.round(p.x), Math.round(p.y));
            self.ctx.closePath();
            self.ctx.strokeStyle = 'hsla(' + p.hue + ', 100%, ' + p.brightness + '%, ' + p.alpha + ')';
            self.ctx.stroke();

            if (self.flickerDensity > 0) {
                var inverseDensity = 50 - self.flickerDensity;
                if (rand(0, inverseDensity) === inverseDensity) {
                    self.ctx.beginPath();
                    self.ctx.arc(Math.round(p.x), Math.round(p.y), rand(p.lineWidth, p.lineWidth + 3) / 2, 0, Math.PI * 2, false)
                    self.ctx.closePath();
                    var randAlpha = rand(50, 100) / 100;
                    self.ctx.fillStyle = 'hsla(' + p.hue + ', 100%, ' + p.brightness + '%, ' + randAlpha + ')';
                    self.ctx.fill();
                }
            }
        };
    }
    // 创建烟花
    self.createFireworks = function (startX, startY, targetX, targetY) {
        var newFirework = {
            x: startX,
            y: startY,
            startX: startX,
            startY: startY,
            hitX: false,
            hitY: false,
            coordLast: [
                { x: startX, y: startY },
                { x: startX, y: startY },
                { x: startX, y: startY }
            ],
            targetX: targetX,
            targetY: targetY,
            speed: self.fworkSpeed,
            angle: Math.atan2(targetY - startY, targetX - startX),
            shockwaveAngle: Math.atan2(targetY - startY, targetX - startX) + (90 * (Math.PI / 180)),
            acceleration: self.fworkAccel / 100,
            hue: self.currentHue,
            brightness: rand(50, 80),
            alpha: rand(50, 100) / 100,
            lineWidth: self.lineWidth
        };
        self.fireworks.push(newFirework);

    };

    // 更新烟花 
    self.updateFireworks = function () {
        var i = self.fireworks.length;

        while (i--) {
            var f = self.fireworks[i];
            self.ctx.lineWidth = f.lineWidth;

            vx = Math.cos(f.angle) * f.speed,
            vy = Math.sin(f.angle) * f.speed;
            f.speed *= 1 + f.acceleration;
            f.coordLast[2].x = f.coordLast[1].x;
            f.coordLast[2].y = f.coordLast[1].y;
            f.coordLast[1].x = f.coordLast[0].x;
            f.coordLast[1].y = f.coordLast[0].y;
            f.coordLast[0].x = f.x;
            f.coordLast[0].y = f.y;

            if (f.startX >= f.targetX) {
                if (f.x + vx <= f.targetX) {
                    f.x = f.targetX;
                    f.hitX = true;
                } else {
                    f.x += vx;
                }
            } else {
                if (f.x + vx >= f.targetX) {
                    f.x = f.targetX;
                    f.hitX = true;
                } else {
                    f.x += vx;
                }
            }

            if (f.startY >= f.targetY) {
                if (f.y + vy <= f.targetY) {
                    f.y = f.targetY;
                    f.hitY = true;
                } else {
                    f.y += vy;
                }
            } else {
                if (f.y + vy >= f.targetY) {
                    f.y = f.targetY;
                    f.hitY = true;
                } else {
                    f.y += vy;
                }
            }

            if (f.hitX && f.hitY) {
                self.createParticles(f.targetX, f.targetY, f.hue);
                self.fireworks.splice(i, 1);

            }
        };
    };
    //绘制烟花
    self.drawFireworks = function () {
        var i = self.fireworks.length;
        self.ctx.globalCompositeOperation = 'lighter';
        while (i--) {
            var f = self.fireworks[i];
            self.ctx.lineWidth = f.lineWidth;

            var coordRand = (rand(1, 3) - 1);
            self.ctx.beginPath();
            self.ctx.moveTo(Math.round(f.coordLast[coordRand].x), Math.round(f.coordLast[coordRand].y));
            self.ctx.lineTo(Math.round(f.x), Math.round(f.y));
            self.ctx.closePath();
            self.ctx.strokeStyle = 'hsla(' + f.hue + ', 100%, ' + f.brightness + '%, ' + f.alpha + ')';
            self.ctx.stroke();

            if (self.showTarget) {
                self.ctx.save();
                self.ctx.beginPath();
                self.ctx.arc(Math.round(f.targetX), Math.round(f.targetY), rand(1, 8), 0, Math.PI * 2, false)
                self.ctx.closePath();
                self.ctx.lineWidth = 1;
                self.ctx.stroke();
                self.ctx.restore();
            }

            if (self.showShockwave) {
                self.ctx.save();
                self.ctx.translate(Math.round(f.x), Math.round(f.y));
                self.ctx.rotate(f.shockwaveAngle);
                self.ctx.beginPath();
                self.ctx.arc(0, 0, 1 * (f.speed / 5), 0, Math.PI, true);
                self.ctx.strokeStyle = 'hsla(' + f.hue + ', 100%, ' + f.brightness + '%, ' + rand(25, 60) / 100 + ')';
                self.ctx.lineWidth = f.lineWidth;
                self.ctx.stroke();
                self.ctx.restore();
            }
        };
    };
    //绑定事件
    self.bindEvents = function () {
        $(window).on('resize', function () {
            clearTimeout(self.timeout);
            self.timeout = setTimeout(function () {
                self.canvas.width = self.cw = $(window).innerWidth();
                self.canvas.height = self.ch = $(window).innerHeight();
                self.ctx.lineCap = 'round';
                self.ctx.lineJoin = 'round';
            }, 100);
        });

        $(self.canvas).on('mousedown', function (e) {
            self.mx = e.pageX - self.canvas.offsetLeft;
            self.my = e.pageY - self.canvas.offsetTop;
            self.currentHue = rand(self.hueMin, self.hueMax);
            self.createFireworks(self.cw / 2, self.ch, self.mx, self.my);

            $(self.canvas).on('mousemove.fireworks', function (e) {
                self.mx = e.pageX - self.canvas.offsetLeft;
                self.my = e.pageY - self.canvas.offsetTop;
                self.currentHue = rand(self.hueMin, self.hueMax);
                self.createFireworks(self.cw / 2, self.ch, self.mx, self.my);
            });
        });

        $(self.canvas).on('mouseup', function (e) {
            $(self.canvas).off('mousemove.fireworks');
        });

    }

    self.clear = function () {
        self.particles = [];
        self.fireworks = [];
        self.ctx.clearRect(0, 0, self.cw, self.ch);
    };

    self.canvasLoop = function () {
        requestAnimFrame(self.canvasLoop, self.canvas);
        self.ctx.globalCompositeOperation = 'destination-out';
        self.ctx.fillStyle = 'rgba(0,0,0,' + self.clearAlpha / 100 + ')';
        self.ctx.fillRect(0, 0, self.cw, self.ch);
        self.updateFireworks();
        self.updateParticles();
        self.drawFireworks();
        self.drawParticles();

    };

    self.init();

    self.showRandom = function () {

        var initialLaunchCount = 50;
        while (initialLaunchCount--) {
            self.currentHue = rand(self.hueMin, self.hueMax);
            self.createFireworks(self.cw / 2, self.ch, rand(50, self.cw - 50), rand(50, self.ch / 2) - 50);
        }
    }
}
    //定时点燃
    //self.showRandom = function () {
    //    setInterval(self.run,3000);
    //}
    //self.run = function () {
    //    var Count = parseInt(Math.random() * 100+50);
    //    while (Count--)
    //        self.currentHue = rand(self.hueMin, self.hueMax);
    //        self.createFireworks(self.cw / 2, self.ch, rand(50, self.cw - 50), rand(50, self.ch / 2) - 50);
    //        }
    //    }


